Synthesis method of moolydenum dioxide ultrathin nanowire bundles for surface-enhanced raman spectroscopy

Abstract

The application discloses a synthesis method of MoO2 ultra-thin nanowire bundles for surface-enhanced Raman spectroscopy, which comprises the following steps: uniformly stirring a mixture of ethylene glycol, deionized water, ammonium molybdate, CTAB and glucose to obtain a precursor mixture, then transferring the precursor mixture into a reaction kettle, reacting at high temperature, transferring the obtained black product into a tube furnace, and heating at ultra-high temperature to obtain MoO2 ultra-thin nanowire bundles. The synthesis method of MoO2 ultra-thin nanowire bundles for surface-enhanced Raman spectroscopy is high in safety and operability, the synthesized material has good chemical stability, can resist strong acid and strong alkali corrosion, and has very high sensitivity as a substrate for surface-enhanced Raman spectroscopy detection, and the Raman scattering signal enhancement factor can reach 2.9*10 7 .

Description

Technical Field

[0001] This invention relates to the field of inorganic advanced materials technology, specifically to a method for synthesizing MoO2 ultrathin nanowire bundles for surface-enhanced Raman spectroscopy. Background Technology

[0002] Since the discovery of surface-enhanced Raman spectroscopy (SERS) on rough Ag surfaces, SERS has been widely applied as an advanced non-destructive analytical technique in fields such as reaction mechanism detection, biomolecule recognition, and trace substance detection. Noble metals, represented by Au and Ag, are the most extensively studied SERS substrates. Although Au substrates have a remarkably high enhancement factor and high stability, their cost is relatively high. As another typical noble metal SERS substrate, Ag substrates have an even higher enhancement factor than Au, but their susceptibility to oxidation makes them unsuitable as typical substrate materials. Therefore, until now, Au is the only commercially available SERS substrate.

[0003] In recent years, besides precious metals, semiconductors have also become a type of SERS substrate that has been studied in depth, such as W 18 O 49 Materials include Cu₂O, MoTe₂, and ZnO. Although semiconductor substrates have been continuously improved, enhancement factors can reach 10. 8 Highly sensitive substrates, such as graphene, conductive polymers, and metal-organic frameworks, often exhibit poor stability and are easily oxidized, decomposed, or corroded. Furthermore, graphene, conductive polymers, and metal-organic frameworks have also been found to possess unexpected SERS activity. However, due to various limitations in fabrication techniques and environmental durability, these substrates are still far from practical SERS applications. Therefore, finding SERS substrates with high sensitivity, high stability, and low cost remains a significant challenge from a large-scale practical application perspective.

[0004] Molybdenum dioxide (MoO2) is an attractive transition metal oxide for a wide range of applications due to its high conductivity, high melting point, and chemical stability, including catalysts, sensors, recording materials, electrochemistry, supercapacitors, lithium-ion batteries, and field emission. Furthermore, localized surface plasmon resonance (LSPR) effects, substrate morphology, and dimensions can be optimized to enhance the Raman scattering effect of SERS substrates.

[0005] Here, we report a MoO2 ultrathin nanowire bundle SERS-active substrate exhibiting a rare strong LSPR effect in the visible light region centered at 520 nm. The detection limit of the probe molecule R6G on the MoO2 ultrathin nanowire bundle is as low as 1 × 10⁻⁶. -11 M, Raman EF is as high as 2.9×10 7More importantly, the MoO2 SERS substrate exhibits excellent chemical stability; it retains its original structure and SERS properties even after acid and alkali treatment and laser irradiation. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide an M for surface-enhanced Raman spectroscopy. O A method for synthesizing O2 ultrathin nanowire bundles, wherein ethylene glycol, water, and ammonium molybdate are used as precursors, hexadecyltrimethylammonium bromide is used as a surfactant, and glucose is used as a reducing agent, and the synthesis is carried out under high temperature and high pressure conditions.

[0007] A type of M for surface-enhanced Raman spectroscopy O The method for synthesizing O2 ultrathin nanowire bundles includes the following steps: mixing ethylene glycol, water, ammonium molybdate, hexadecyltrimethylammonium bromide (CTAB) and glucose to obtain a precursor mixture, then transferring the precursor mixture to a reaction vessel and reacting it at high temperature. The resulting black product is transferred to a tube furnace and heated to ultra-high temperature to obtain MoO2 ultrathin nanowire bundles.

[0008] The M for surface-enhanced Raman spectroscopy described in this invention O A method for synthesizing O2 ultrathin nanowire bundles, wherein the ethylene glycol is 30 mL, the deionized water is 30 mL, the ammonium molybdate is 1 mmol, the CTAB is 15 mmol, and the glucose is 0.5 g.

[0009] The M for surface-enhanced Raman spectroscopy described in this invention O A method for synthesizing O2 ultrathin nanowire bundles, wherein the temperature is raised from room temperature to 180°C and held for 24 hours, and then the reactor is cooled to room temperature.

[0010] The M for surface-enhanced Raman spectroscopy described in this invention O A method for synthesizing O2 ultrathin nanowire bundles, wherein after the reaction vessel is cooled to room temperature, the solution in the liner of the reaction vessel is poured into a 50 mL centrifuge tube, the solution in the centrifuge tube is washed three times with anhydrous ethanol, centrifuged to obtain a black precipitate, and then placed in a vacuum drying oven at 50 °C to dry.

[0011] The M for surface-enhanced Raman spectroscopy described in this invention O A method for synthesizing O2 ultrathin nanowire bundles involves placing a black product in a ceramic boat and loading it into a tube furnace. Under an N2 atmosphere, the temperature is programmed to rise to 700°C at a heating rate of 10°C / min and held for 2 hours, followed by natural cooling to room temperature.

[0012] The M for surface-enhanced Raman spectroscopy described in this invention OA method for synthesizing O2 ultrathin nanowire bundles, wherein the reaction vessel is a high-pressure vessel with a polytetrafluoroethylene liner.

[0013] This invention is used for surface-enhanced Raman spectroscopy. O The method for synthesizing O2 ultrathin nanowire bundles differs from existing technologies in that:

[0014] This invention is used for surface-enhanced Raman spectroscopy. O The synthesis method of O2 ultrathin nanowire bundles is highly safe and easy to operate. The synthesized material has good chemical stability and can withstand strong acid and alkali corrosion. Furthermore, it exhibits very high sensitivity as a substrate for surface-enhanced Raman spectroscopy, with a Raman scattering signal enhancement factor reaching 2.9 × 10⁻⁶. 7 .

[0015] The method of this invention synthesizes M with high sensitivity surface-enhanced Raman spectroscopy detection capability. O O2 ultrathin nanowire bundles ( Figure 1 This technology combines electromagnetic field enhancement and chemical enhancement effects, and can be directly used to detect trace amounts of harmful molecules, with a detection sensitivity of up to 10. -8 M( Figure 2 The Raman enhancement factor is as high as 2.9 × 10⁻⁶. 7 .

[0016] The following description, in conjunction with the accompanying drawings, describes the M-type surface-enhanced Raman spectroscopy of the present invention. O The synthesis method of O2 ultrathin nanowire bundles will be further explained. Attached Figure Description

[0017] Figure 1 M obtained by the method of the present invention O Photographs of O2 ultrathin nanowire bundles;

[0018] Figure 2 M in the method of the present invention O 10 obtained on an O2 ultrathin nanowire bundle SERS substrate -6 M-Rhodamine 6G molecular signal. Detailed Implementation

[0019] Example 1

[0020] A method for synthesizing MoO2 ultrathin nanowire bundles for surface-enhanced Raman spectroscopy includes the following steps: A mixture of 30 mL ethylene glycol, 30 mL deionized water, 1 mmol ammonium molybdate, 15 mmol CTAB, and 0.5 g glucose is stirred until homogeneous to obtain a precursor mixture. This precursor mixture is placed in a reaction vessel (a high-pressure reactor with a polytetrafluoroethylene liner), heated from room temperature to 180°C, and maintained for 24 hours. The reaction vessel is then cooled to room temperature. After cooling, the solution in the reaction vessel liner is poured into a 50 mL centrifuge tube. The solution in the centrifuge tube is washed three times with anhydrous ethanol, centrifuged to obtain a black precipitate, and dried in a vacuum drying oven at 50°C. The black product is placed in a ceramic boat and loaded into a tube furnace. Under a N2 atmosphere, the temperature is programmed to rise to 700°C at a rate of 10°C / min and maintained for 2 hours, then naturally cooled to room temperature. The obtained products were characterized by XRD, confocal Raman microscopy, SEM, TEM, and EDX. O O2 ultrathin nanowire bundles, used as a SERS substrate, achieve a detection concentration limit of 10 for analyte molecules. -11 M.

[0021] Example 2

[0022] A mixture of 30 mL ethylene glycol and 30 mL deionized water was mixed with 1 mmol ammonium molybdate, 15 mmol cetyltrimethylammonium bromide (CTAB), and 0.5 g glucose. The mixture was stirred at room temperature for 30 minutes, then transferred to a PTFE-lined autoclave and reacted at 180 °C for 24 hours. After natural cooling to room temperature, the resulting black product was washed three times with distilled water and anhydrous ethanol and dried under vacuum at 50 °C. 0.1 g of the black powder was placed in a quartz ceramic boat and loaded into a tube furnace. N2 was introduced into the furnace at a flow rate of 3 mL / s, and the temperature was increased to 700 °C at a heating rate of 10 °C / min. The reaction was carried out under these conditions for 2 hours, then naturally cooled to room temperature. The obtained product was characterized by XRD, confocal Raman microscopy, SEM, TEM, and EDX. O O2 ultrathin nanowire bundles, used as a SERS substrate, achieve a detection concentration limit of 10 for analyte molecules. -11 M.

[0023] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for synthesizing MoO2 ultrathin nanowire bundles for surface-enhanced Raman spectroscopy, characterized in that: The process includes the following steps: 30 mL of ethylene glycol, 30 mL of deionized water, 1 mmol of ammonium molybdate, 15 mmol of CTAB, and 0.5 g of glucose are mixed and stirred to obtain a precursor mixture. This precursor mixture is placed in a polytetrafluoroethylene-lined autoclave, heated from room temperature to 180°C, and maintained for 24 hours. The autoclave is then cooled to room temperature. After cooling, the solution in the autoclave liner is poured into a 50 mL centrifuge tube. The solution in the centrifuge tube is washed three times with anhydrous ethanol, centrifuged to obtain a black precipitate, and dried in a vacuum drying oven at 50°C. The black precipitate is placed in a ceramic boat and then placed in a tube furnace. Under a N2 atmosphere, the temperature is programmed to rise to 700°C at a rate of 10°C / min and maintained for 2 hours, then naturally cooled to room temperature. The obtained product is characterized by XRD, confocal Raman microscopy, SEM, TEM, and EDX. O O2 ultrathin nanowire bundles, used as a SERS substrate, achieve a detection concentration limit of 10 for analyte molecules. -11 M.

Images